Compact switch having a simple breaking contact and associated arc extinction means



COMPACT SWITCH HAVING A SIMPLE BREAKING CONTACT AND ASSOCIATED ARC EXTINCTION MEANS Filed D90. 4, 1961 g- 1966 A. FEHRENBACH ETAL 3, 0,170

//VSUL A TlON RL-fvec: Idzvenbaciz \QLexaner Prries Heinrich Frcw5 Inventors Httovnag United States Patent L 1 Claim. oi. 200-144 The present invention relates generally to switches, and more particularly to compact switches having simple breaking contacts.

In the switching art, efforts are constantly being made to increase performance of switches while, at the same time, reducing the dimensions thereof. It is very difficult to accomplish both of these objects in switching apparatus because usually a reduction of the dimensions of the apparatus causes an impairment of the performance of the switch. In order to satisfy both demands, a special design is required with respect to the space distribution and the other constructional design features. Those switches of the simple and multiple breaking type, and especially those of small size, which have been created thus far are not yet satisfactory.

In switching apparatus of the simple breaking contact type, compact physical dimensions may be readily achieved, but there are drawbacks in known switches of this type because the other switch features do not satisfy the demands which are required due to the small size. As an example, a switch of relatively great length is required in switching apparatus of the simple breaking contact type wherein the carrier of a swivelling bridge is arranged in the bottom portion of the switch and is oriented parallel to the bottom surface of the housing. The electric arc in such a switch is directed in the longitudinal direction of the switch. The great length of the switch which is required does not permit installation of the switch in certain types of apparatus, for example, in meter boards.

A further disadvantage of known switching apparatus is that a comparatively large cavity is provided at the bottom of the switch, and is open to the atmosphere, and houses voltage carrying connecting terminals or connection parts. This cavity occupies a large portion of the height of the switch without being advantageous in the actual switching performance. Furthermore, the cavity must be covered by a plate which has to be fastened thereto by special means.

With these defects of the prior art in mind, it is a main object of this invention to provide a small, compact switching apparatus having simple breaking contacts.

A further object of this invention is to provide a switching apparatus of the type described wherein the spacing and orientation of the various elements thereof provide a small switch which does not impair the switching performance.

Another object of this invention is to provide a switch which includes very effective means for arc extinction.

These objects and others ancillary thereto are accomplished according to preferred embodiments of the invention, wherein a switch such as an automatic switch, is provided with the switching mechanism being housed in an upper portion of the switching apparatus and with the electric arc chamber formed in a bottom portion of the switch. The bottom portion of the switch is of box design so that the rectangular bottom wall of the arc chamber also acts as the bottom wall of the switch and the breaking point of the contacts is provided near a narrow dimension or side of the arc chamber. This is done in such a manner that the contacts, with their current supply, form a U-shaped current supply loop which is oriented to be perpendicular with the bottom wall of the chamber.

Preferably, the arc chamber is equipped with an arrangement of arc extinguishing baflies which are parallel to the bottom wall and which occupy the major portion of the space in the arc chamber. The contact assembly is located in the remainder of this chamber space and comprises a stationary contact arranged at one narrow side of the chamber and fixed at right angles or obliquely to the bottom wall of the chamber. A movable contact, preferably a swivel or push type contact is also provided to cooperate with the stationary contact. The swivel arm of the swivel contact, or the push rod of a push type contact, is arranged parallel or substantially parallel to the stationary contact and is controlled by the mechanism arranged above the arc chamber.

Additional objects and advantages of the present invention will become apparent upon consideration of the following description when taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a vertical sectional view taken through the apparatus of the present invention with the arc chamber and the contact assembly shown in detail, while the upper portion thereof is only shown in dashed lines.

FIGURE 2 is a horizontal sectional view taken substantially along the plane defined by line 22 of FIGURE 1.

FIGURE 3 is a fragmentary sectional view of the contact assembly using a push type contact.

FIGURE 4 is a fragmentary sectional view of one special type of stationary contact, and is taken substantially along the plane defined by line 4-4 of FIGURE 5.

Figure 5 is a vertical sectional view taken substantially along the plane defined by line 5-5 of FIGURE 4.

With more particular reference to the drawings, FIG- URES 1 and 2 illustrate a switch having a rectangular box-like bottom housing 1, having lugs 2 and -3 at each narrow side thereof, respectively, which hold connecting terminals 4 and '5 in place. The interior 6 of the bottom housing 1 defines an arc chamber in which are extinguishing baffles 7 are arranged which occupy by far the greater portion of this chamber space. They are spaced from each other throughout the entire height of the arc extinguishing chamber and are disposed parallel to the floor or bottom of the arc chamber. These are extinguishing baflles are designed to be symmetrical with respect to their longitudinal axes and each abuts against one narrow wall of the arc chamber along a narrow edge thereof.

The corners of these narrow edges of the baflles have circular arc cutout portions which correspond to a reinforcement 1a of the bottom housing of the switch and which protrude into the arc chamber. A corresponding further reinforcement 1b is provided in the bottom hous- 0 ing of the switch and is disposed diagonally opposite the reinforced portion 1a. Other cutout corners 6a are provided in the portions of the arc extinguishing baflles 7 adjacent cutouts 1a and together define a ventilating duct which communicates with the atmosphere in a manner which is not shown.

These arc extinguishing baffles can be fairly easily mounted because of their symmetry with respect to their longitudinal axes. A pair of inwardly extending and oppositely directed lugs and 1d are provided in the bottom portion of the switch, and the baffles are provided with corresponding slots to accommodate these lugs. The baffles are therefore easily placed into position and are guided by means of the lugs 1c and 1d and the reinforcement 1a, and are retained at a distance from each other by means of spacers (not shown).

These baffles are provided with V-shaped apertures 7a along their narrow ends opposite the ends having the cutout portions 1a and 6a. A stationary contact 8 is arranged on the narrow or shorter wall of the arc chamber opposite these apertures 7a, and occupies the entire height of the arc chamber. This contact 8 extends downwardly and has an angled portion 8a extending parallel to the bottom of the arc chamber and close to the lowermost of the arc extinguishing baflles. The other end of the stationary contact 8 is provided with an upper-angled portion 812 which is connected or integral with connecting terminal 4.

The movable contact in the embodiment of FIGURES 1 and 2 is a contact 9 which cooperates with the stationary contact 8. This contact has a contact element 27 arranged on a swivel arm 10 which rotates about an axis 12 disposed above the arc chamber and in the chamber 11 containing the mechanism for the switch.

The contact element 27 is at substantially a right angle with respect to stationary contact '8. This element is generally L-shaped and includes a short rounded leg 28 at the end of arm 10 and disposed generally parallel thereto. The other leg 29 partially encloses the lower end of arm 10 and is shaped to provide an easy run-off path for the arc. Leg 29 is disposed substantially parallel to batfles 7. The V-shaped apertures 7a are provided to permit swivelling movement of, element 27, which would otherwise be prevented from a full range of movement by the adjacent ends of the baffles 7.

Swivel arm 10 projects through an aperture 13 of a cover plate 14 which seals the arc chamber from the mechanism chamber. A movable plate 15 is disposed on top of cover plate 14, and is provided with an opening through which the swivel arm may pass so that this plate 15 moves back and forth with the movement of arm 10. The mechanism chamber which houses the switching mechanism and the magnetic and, if desired, the thermal trigger elements, is enclosed by an upper housing cap 1 6 which is fastened to the bottom portion of the switch at the reinforced corners 1a and 1b, such as by means of holes 25 and 26, in a manner which is not shown. The current in this switch is supplied from connecting terminal 4, passes along stationary contact 8 to the contact 9, through the arm 10, and then along conductor 17 via the trigger members to the connecting terminal 5- The switch is particularly advantageous because of its contact arrangement due to the fact that the contact assembly including the stationary contact, the contact element, and the swivel arm, together form a U-shaped arc extinguishing loop '18, indicated in dashed lines, and which is oriented to be perpendicular to the bottom of the arc'chamber. Because of this arrangement very little space is required for the contact assembly particularly in the longitudinal direction, and a good are extinguishing effect is nevertheless achieved.

Due to the U-shaped current supply loop provided at the contact point of the contacts, an arc extinguishing effect is achieved which drives the base point of the arc down the stationary contact piece and in the direction of the arc extinguishing baffie arrangement. Preferably, the upper baffle of the arrangement is conductively connected with terminal 5, so that flashing over the arc from the movable contact to this baffie is facilitated. A further advantage is provided by this switch because of its design with the bottom portion being completely occupied by the arc chamber. The bottom wall of the arc chamber is, at the same time, the bottom of the switch so that a size reduction is possible with respect to the height of the switch. If desired the connecting terminals and holes for fastening the switch may be arranged diagonally op posite one another on the lateral lugs of the bottom housing. All the terminal parts are arranged in or near the lateral lugs of the lower housing.

As shown in FIGURE 3, a push type contact may be' used as the movable contact. In this embodiment the stationary contact S has its central portion arranged obliquely with respect to the bottom of the arc chamber. A movable contact 19 is oriented substantially prependicularly with respect to the arc chamber and moves in its own plane. The displacement in the direction of arrow 20 will be downwardly in the closing position of the contact and will form a U-sha'ped current supply loop 18.

with the upper part of the stationary contact similar to the embodiment of FIGURE 1. This device will require even less space than that of the pivotable contact type, but is more cumbersome with respect to its control.

In order to increase the arc extinguishing effect in the switch according to the present invention the end 8a of the stationary contact 8, which is disposed along the bottom of the arc chamber, may be provided with a ferromagnetic U-shaped guide 21, see FIGURES 4 and 5. This guide is disposed at the bottom of the arc chamber with its web portion beneath the contact portion 8a. It flanks the latter with upwardly extending legs 22 which extend beyond this contact portion. At one end, this guide has an upwardly bent portion 24 extending parallel to a portion of the central section 80 of the stationary contact 8. An intermediate layer 23 of insulating material is provided between the stationary contact and the guide.

The ferromagnetic guide provides a magnetic field between the leg ends 22 projecting beyond the contacting piece, due to the current in the contact 8, which supports the arc extinguishing eifect of the U-shaped current loop in the bottom portion of the arc chamber, where the loop effect is no longer fully effective. Faster movement of the base points of the arc along the extension of the stationary contact 8 is obtained, and the arc thus moves faster into the arc extinguishing baffle arrangement.

It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

What is claimed is:

A switch, comprising, in combination:

(a) a switch housing having a first section and a second section defining a rectangular arc extinguishing chamber having a rectangular bottom wall;

(b) a switching mechanism in said first section;

(c) arc extinguishing means in said arc extinguishing chamber and including a plurality of parallel arc extinguishing bafiles spaced from each throughout the entire height of said chamber and occupying the major portion of said chamber; and

(d) a contact assembly in said are extinguishing chamber and including (1) a movable contact having a movable contact element thereon and mounted to open in the direction of the baflles, said movable contact being mounted for pivoting movement, and

(2) a stationary contact, said contacts being dis-- posed adjacent the ends of the baffles and at one end of said rectangular arc extinguishing chamber so that contact separation occurs at this end, the stationary contact together with its current lead forming in cooperation with the movable contact and its carrier a U-shaped blow-out loop, said loop being oriented per pendicularly to the planes of said bafiles, and the place of contact separation being located at the place where the loop changes direction said stationary contact being disposed on one side of the chamber, in the plane of the narrow dimension thereof at a right angle to the planes of the baflles, and generally parallel to said movable contact when said contacts are in contact, said stationary contact extending for at least the entire height of the plurality of bafiles and having a lower portion extending parallel to said bottom wall of said chamber, the elements in said chamber completely filling the chamber and the ends of said second section being thickened to provide sockets for holding the switch terminals and for mounting the switch, said baflles being disposed parallel to said bottom wall of said chamber.

References Cited by the Examiner UNITED STATES PATENTS 3 1934 Leyhausen 200-147 1/1936 Austin 200147 1/ 1939 Wulsten 200147 12/ 1943 Walle 200147 1/1951 Lerstrup 200-147 3/ 1952 Kalaway 200147 10/ 1956 Cellerini 200147 4/ 1958 Coleman 200147 3/ 1964 Stettner 200144 FOREIGN PATENTS 10/ 1940 Germany. 3/ 1959 Germany. 9/ 1959 Germany. 12/ 1941 Sweden.

ROBERT K. SCHAEFER, Primary Examiner. R. S. MACQN, Assistant Examiner. 

